1. Field of the Invention
This invention relates generally to apparatus for reproducing signals recorded on a selected one of a plurality of discs having different diameters, and more particularly is directed to improvements in disc players of the front-loading type capable of selectively reproducing at least two kinds of discs, such as, an optical video disc of relatively large diameter, hereinafter referred to as an LD, and a compact disc of relatively small diameter, hereinafter referred to as a CD.
2. Description of the Prior Art
A so-called compatible disc player has been proposed for selectively reproducing information recorded on large-diameter optical video discs or LDs and on small-diameter compact discs CDs.
In one such proposed CD/LD compatible disc player, a box-shaped casing or housing is provided with an opening at the front thereof, a disc-transporting tray is movable horizontally through the front opening for receiving either a CD or LD at the outside of the casing and then carrying the received disc to within the casing, a first disc driving mechanism extending from a chassis within the casing for rotatably driving the LD when the latter is operatively positioned within the casing, another or second disc driving mechanism mounted on the chassis for swinging movement through approximately 90.degree. from an operative vertical position for driving a CD and a stowed position for avoiding interference with playback of an LD, and an optical pickup for reading signals recording on either a CD or an LD while moving in a radial direction relative thereto.
In the already proposed CD/LD compatible disc player, the disc-transporting tray includes a substantially rectangular plate molded of resin and having a cutout formed therein extending rearwardly from a central portion of the tray to the center of a rear part thereof to permit an optical pick-up to move along such cutout and scan an optical disc therethrough. A first carrier or relatively large diameter disc mounting portion for guiding an LD is formed on a substantially centered part of the disc-transporting tray and includes a circular recess of a diameter slightly larger than that of the LD for receiving the latter. A second carrier or relatively small diameter disc mounting portion is formed independently of the first carrier and is capable of reciprocal movement relative to the latter along the cutout. Such second carrier includes substantially rectangular slide plates bridging the opposite side edges of the cutout and is formed with a circularly recessed portion of a diameter slightly larger than that of the CD so as to readily receive the latter.
When the disc-transporting tray is extended forwardly through the opening at the front of the casing or housing, both the first and second carriers are concentrically positioned at the center of the tray. On the other hand, when the disc transporting tray is moved into the housing by means of a loading mechanism, the second carrier is simultaneously moved relative to the tray at a relatively high speed in the rearward direction so that the second carrier is quickly displaced to a predetermined CD playback position at the rearmost part of the tray within the housing. When signals recorded on an LD are to be reproduced, the disc-transporting tray is moved downwardly within the player casing by means of the loading mechanism, and the LD received by the first carrier is then held between a turntable driven by a spindle motor of the respective disc driving mechanism and a chuck provided for the LD so as to be rotated at a relatively high speed while signals recorded on the LD are read by the optical pickup which is moved relative to the LD in a radial direction of the latter. During such reading or playback of the signals recorded on an LD, the spindle motor of the CD drive mechanism is angularly displaced through 90.degree. from its operative vertical position so as to avoid interference with the movements of the optical pickup radially in respect to the LD.
On the other hand, when signals recorded on a CD are to be reproduced, the disc transporting tray is again moved downwardly after being inserted horizontally into the player casing, and the CD received by the second carrier is gripped between a CD chuck and a turntable on the spindle motor of the CD drive mechanism which, at this time, extends vertically, so that the CD is rotatably driven while the signals recorded on the CD are read by means of the optical pickup during movement of the latter in the radial direction of the CD.
However, since the previously proposed CD/LD compatible disc player has the disc transporting tray thereof provided with independent LD and CD carriers, with the CD carrier being slidable relative to the LD carrier above the latter along a path extending rearwardly from the center of the LD carrier, the depth of the disc player casing cannot be minimized. Further, the thickness or height of the disc transporting tray cannot be desirably reduced while maintaining a required rigidity of the structure. Moreover, in view of the need to effect movement of the CD carrier relative to the LD carrier, an additional driving mechanism is required for effecting such movements so that the number of parts employed in the disc player and the complexity of its construction are increased with the result that the cost of the apparatus is undesirably raised.
Finally, for ejecting a CD at the completion of the playback of the recorded signals thereon, the disc-transporting tray is extended forwardly through the opening of the disc player casing and at the same time, the LD carrier and the CD carrier are moved relative to each other so as to be finally disposed concentrically at the central portion of the tray. Thus, in order to fully expose the CD carrier for permitting convenient removal of the CD therefrom, the disc-transporting tray has to be in its fully extended position relative to the player casing. The movement of disc-transporting tray to and from its fully extended position is relatively time consuming with the result that an undesirably long period of time is required for either ejecting a CD at the completion of the playback thereof, or for exchanging one CD or LD for another.